1. Field of the Invention
The invention relates to an apparatus and a method for sterilizing components, matter and infectious waste materials using an ultra high pressure vessel and a fluid medium to apply isostatic pressure to the matter or waste material. Specifically, the invention relates to an apparatus and a method for sterilizing matter and especially, organic matter such as infectious waste materials using ultra high isostatic pressure.
2. Description of the Background Art
Growing concern for the environment is having a major impact on the cost of sterilizing medical or infectious waste materials. Increases in health care and medical technology, combined with an increasing life span for the average person, have resulted in large increases in the number of hospital patents and production of infectious waste materials. Currently, the average hospital patient generate between 2.8 and 3 pounds of medical waste per day. Up to about 15 percent of this matter is defined as "infectious". Recent occurrences of infectious waste materials washing up on U.S. beaches and the growing fear of AIDS are increasing the public's concern over sterilization and disposal of medical waste materials.
Federal and State regulations require the sterilization of all infectious waste materials prior to disposal. Current methods of sterilization include incineration, mechanical and chemical treatment, steam/compaction, and microwave shredding. Incineration is a widely accepted method of disposal of infectious waste materials. Advantages of this method include the acceptability of the procedure by regulatory agencies, high volume reduction (about 90 percent of the material is destroyed), and the conversion of the waste into an unrecognizable state. However, incineration poses a series of problems. Incinerators have maintenance and operational difficulties, temperature variability, licensing and permit requirements, air emissions problems, and ash disposal problems. Operational costs, such as labor, maintenance, and fuel expenses, combine to make incineration one of the most costly methods of sterilization with processing costs averaging 8 to 9 cents per pound and 2 cents per pound for disposal. Many states now require emission scrubbers to improve air emissions. However, scrubbers also require a source of water, which presents an additional problem in states suffering from water shortages. The requirement of new pollution monitoring equipment and concern over the pollutants produced from burning plastic infectious waste disposal bags further add to incineration disadvantages.
Another accepted method of infectious waste disposal is the mechanical and chemical treatment of infectious waste materials. Advantages of this method of treatment include the acceptability of such processed materials by land fills, unrecognizable materials, high dilution and volume ratios, process on demand cycles, no order, and no air emissions. Disadvantages of this method of treatment include specialized personnel training, consumable parts, suspended solids, storage and handling of chlorine, some regulatory problems, and a frequent requirement for sewer permits. Materials are processed at a rate of 5 cents per pound and 1 cent per pound for disposal.
Steam/Compaction treatment of matter is a generally accepted procedure for general matter and infectious waste materials. Advantages of this method include a 5:1 volume reduction, easy operation, no double handling of materials, no air emissions, no licensing or permits. Disadvantages of this method of treatment include the land fill acceptability, long cycle time, requirement for validation and monitoring equipment, and odor. The cost for processing matter by this method averages 4 cents per pound and 2 cents per pound for disposal. This method has difficulty effectively sterilizing the entire spectrum of microbes.
One of the newest methods of sterilization is microwave shredding of waste matter. Advantages of this method of treatment include rendering the waste unrecognizable, an 8:1 volume reduction, no liquid effluent, no air emissions, and easy operation. Disadvantages of this method of treatment include long delivery dates for new equipment, replacement of consumable parts, restrictions on waste content, such as metals and moisture, long hold times, odor, and low destruction quality. Processing costs average 7 cents to 10 cents per pound and disposal costs are not determined at this time.
The sterilization of infectious waste materials encounters a number of additional problems than those problems identified above. Most of the above listed technologies cannot be scaled down to a size and cost of acquisition and operation that fits the low volume producers of infectious waste materials such private hospitals. Strict procedures and regulations governing the transportation of hazardous waste materials from a producer to a central disposal site significantly adds to the cost of the disposal. This cost averages about 6 cents per pound.
Currently, the industry is lacking an apparatus and a method for sterilizing matter, including infectious waste materials, that is environmentally acceptable, cost effective, and can be scaled to meet the needs of either larger or small waste producers.